Artificial leg



(No Model.)

R. C. DUNHAM;

ARTIFICIAL LEG.

No. 336,904. PatentedMaJr. 2, 1886.

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NrTnD STATES 'PATENT Fries ARTIFICIAL LEG.

SPECIFICATION forming part of Letters Patent No. 336,904, dated March 2.1886.

Application led April 16, 1885. Serial No. 162.414.

.of which the following is a specification.

My invention relates, principally, to articial legs, my purpose being toprovide a leg which may be readily adjusted to a desired comfortableposition, or may as readily be entirely removed, and in which theseveral movements of the knee, ankle, and foot joints are substantiallythe same as in the natural leg.

In the accompanying drawings, Figure 1 shows said articial leg (sideelevation) ready tion of the leg from the knee -joint downward beingshown in vertical section in order to better illustrate the internalworking parts. Fig. 2 is a sectional view on line m .fc of Fig. l,showing the spring-latch which I have employed to furnish the necessaryadjustment for persons of ditferentheights, as hereinafterl described indetail.

Although I have illustrated and intend to describe a leg to be attachedabove the kneejoint,tl1e lower part of my improved leg-that is to say,the foot and ankle-may be used with equally satisfactory resultsindependent of the knee-joint. The shell or case of said leg is formedpreferably of wood, papier-ma` che, or other similar yet stili"material.

In the annexed drawings, A represents the thigh portion, B the calf, andC the foot.

The thigh portion A is pivoted in section B to form the kneejoint, andhas projecting downward below its pivotal point a tenon or extension, a.Attached to the front side of said extension is a chain, b, which,passing.

downward and rearward around the channeled rounded end of saidextension, is attached to the free end of a spring, c. This spring c isconcealedwithin the hollow section B, and is secured at its lower end tosaid section at or near the point occupied by the shinbone in thenatural leg, and acts with a constant tendency to throw the calf andfoot sec- (No model.)

tions forward. The rear side of section A is cut under, as at d, so thatit may pass within section B as the knee is bent forward, but theopposite or front side overlaps said section B, as shown at d', thusforming a stop to limit the forward movement of the lower section whenraised from the ground and under the influence ot` the spring c.

On the lower end of section B is a tenon, e, which is pivoted in thefoot-section to form the ankle-joint. This joint has also a downwardextension rounded and channeled substantially the same as that describedabove.

The pivot which connects the tenon e with the foot-section is surroundedwith a packing, e',

of rubber or other similar flexible material,

to relieve said joint from the unnatural and disagreeable effect whichresults from the use of a rigid metallic joint. As a simple'and cheapmethod of producing said packing e I have used sections of rubbertubing, which- I slip over the metal rivet or screw. In order to providea natural movement at the ankle and heel I have employed a novelarrangiement of chains and springs, as follows:

E represents a spring secured well forward'f in the foot-section, andprovided near its free end with perforated lugs, staples, or othersimilar eyes, h h. The leg-section B is mortised at the front and rearsides, (see i 1,) and is drilled from its lower end to receive eyeboltsk k', said bolts being held in proper position by nuts located in themortises t' i. Eyebolt 7c is connected to the spring-staple h' by achain, a', which chain passes around extension e. n to staple h, the twochains crossing each other at the lower end of extension e, being soadjusted relative to each other that theyact to bring the foot-sectionto its normal position, whether bent forward or backward. It will bereadily understoodfthat should stiffer or more elastic ankle-joint berequired or desired, the staples h and h should be brought nearer eachother or carried farther apart, according to the requirementof the case.

The toe-section D is pivoted in the foot-section, and is held in itsnormal position by an end bearing-spring, o, located within the foot Theeyebolt k is connected by chain IOO and acting against the rabbetedupper side of said toe-section. By the use of this fiat sheetmetalspring so set that the upward movement ofv the toe'sections exerts anendwise pressure on the spring and deflects its middle portion sidewise,I am enabled to bend the spring more for al given movement ofthetoe-section than is the case with other arrangements of sheet-metalsprings in artificial feet, and consequently I obtain a quicker-actingspring. It should also be noticed that the forward end of thefoot-section extends forward beyond the toe-joint and covers said jointand the actuating spring.

Having thus described the construction of my newly improved artificialleg, I will proceed to describe the attachments by which it is securedto the wearer, andby means of which it may be adjusted to fit persons ofdifferent heights and sizes.

Secured to the side of section A is a metallic strap, p, whose upper endis preferably riveted to a similar strap, r, provided with a series ofperforations, s. This perforated strap fr' is arranged to slide within ametallic piece, F, on whose outer side is hung a springlpressedsnap-latch, G, one end of said latch being of a size and shape to enterthe perforations s, as shown in Fig. 2, in which position it abutsagainst the backside of piece F. It will thus 'be seen that by changinglatch G from hole to hole, any desired adjustment within the range orlimit of said holes may be easily attained, and it will be further seenthat when it is desired to remove the leg it is only necessary to springopen theV latch G and drop said leg. The metallic strap p isstrengthened and supported either on the front or back side, or on bothsides, as shown, by braces B B, whose lower ends are secured to theleg-section A,

vand whose upper ends are secured, preferably, bythe same rivet whichconnects the rnetallic sfrapsp and i'. At a convenient point Aabovelatch G, I have attached a pad, H, and

,flexible strap I, which is buckled around the body to assist in'holding the several parts in proper position, and at the eXtremeupperend of the metallic side strap I have also provided a crutch, K,which I tind in practice relieves the pressure on the stump of thenatural leg without causing undue inconvenience to the wearer.

In place of the several chains employed to connect the working parts,cords could be used with fairly satisfactory results; but I nd thechains act with less tendency to stretch or wear, and as they arecontinually strained Ytaut by their connecting-springs they are alsoVleave quite a space between lsaid sections on the-upper side, and withendWise-acting rubber springs in the forni of rounded blocks set inholes in the confronting Walls of the two sections, the open spacebetween said sections over the toe-joint being covered by a strip ofleather or canvas, which also serves as a stop to prevent the rubbersprings from throwing the toe part beyond the properhorizontal line ofthe foot. The forward end of the foot-section is in the same verticalplane as is theaxis of the toejoint. Another patent shows the pivotedtoe and foot sections in connection with a flat sheet-metal spring,having one end securedto the foot-section, while its opposite end restsin a recess in the toe'section back of itsjoint, whereby the spring isacted upon only by a sidewise pressure, and forces the forward end ofthe toesection downward until a stop arrests its movement. The seambetween the toe and foot sections is back of the pivot or toe joint. Allof said prior art is hereby disclaimed.

Having thus described my invention, IV

claim- 1. The leg-section B, pivoted in the footsection, as shown, aspring within the foot-sec tion, and the crossed chains fn n', connectedat 9o ing a rabbet on its upper side at a point fo'rward of its pivot'oraxis, the foot-section C, jointed or pivoted to said toe-section, andthe iiat sheet-metal spring with one end secured to the foot-section,and having its opposite end resting inthe rabbet of the toe-section at apoint above and forward of the toejoint, so as to be deflected by anendwise pressure, substantially as described, and for the purposespecified.

3. Sections A and B, pivotally joined and provided with the strap d', incombination with spring c, securedl to section B, and the chain b,having one end secured to section A and its opposite end to one end ofsaid spring, said parts being so connected to each other that saidspring acts to hold the leg in its normal position, substantially asdescribed.

4. In combination with au artificial leg, a metallic strap or bracecomposed of two or more sections, one of said sections being formed witha series ofperforations, the other sections being provided witha-spring-pressed latch adapted to engage and interlock with the saidperforations, and a suitable iiexble strap, by means of which thecomplete metallic strap may be secured to the body of the wearer, allsubstantially as and for the object set forth.

5. In combination with an artificial leg, a crutch, a metallic strap orbrace connecting said leg and crutch yand adapted to be adjustedlongitudinally, and a iiexible body-encircling strap, by which saidcrutch and metallic brace are held in a desired position, substantiallyas described, and for the purpose specified.

6. In an artificial limb, a leg-section, afoot- Ico section, and aconnecting rivet or screw havening-braces, B', when used, substantiallyas ing a. metallic 0r otherwise solid core, and a herein described, andf or the purpose speciperipheral Washer of rubber or other similar ed.yielding material, all being combined as herein 5 described, and for theobject specified.

7. In combination with the thighsection A, metallic strap p and one ormore strength- RALPH C. DUNHAM. Witnesses:

JOHN P. BARTLETT, JOHN EDWARDS, Jr.

